Flap-valve.



Patented Apr. 2, 1912.

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CLARENCE N. SCOTT, 0F HOUSTON, TEXAS, ASSIGNOR TO INTERNATIONAL STEAM PUMP COMPANY, A CORPORATION OF NEW JERSEY.

FLAP-VALVE.

Application filed August 4, 1911.

To all whom it may concern:

Be it known that I, CLARENCE N. Soon, a subject of the King of Great Britain, residing at Houston, county of Harris, and State of Texas, have invented certain new and useful Improvements in Flap-Valves, fully described and represented in the following-specification and the accompanying drawings, forming a part of the same.

This invention relates to an improved flap valve intended especially for use in large compressors or blowing engines, but generally applicable for flap valve uses and with either liquids or gases.

In the present blowing engine practice, flap valves formed of elastic plates are commonly used, which are opened by the air pressure and of suflicient elasticity to seat after the discharge stroke. A serious difficulty in such valves results from the fact that it is connnereially impracticable to secure perfectly flat plates, the rolling of the plates resulting in curvature in both directions so thatthe plates ma best be described as buckled. The resul is that the valves will notlie flat against the seats, and when forced against the seats by pressure an abnormal stress is set up in the valve plate, which applied frequently soon results in plate fracture. Moreover, the valves with flat valve seats are not under sutlicient tension to seat before the piston reverses, so that they are then seated with considerable force by the air pressure which racks the valves and is liable to cause the corners of the valve plates to break off. The valve plates with flat valve seats, moreover, are subject to reversal of stress, the outer fibers being alternately under and relieved from tension or compression, resulting in weakening and shortening the life of the buckled valve plates. I avoid these difliculties, and greatly lengthen the life of the valve plates, by using a curved seat and backing the valve plates with one or more spring plates pressing upon the valve, several of these spring plates preferably being used and decreasing in width, so that the pressure of the spring plates decreases toward the free edge of the valve, and these spring plates are preferably cut away to form fingers extending toward the free edge of the valve. With the curved seat, the initial spring tension on the valve plates is increased, thus securing the seating of the valve when the piston has completed Specification of Letters Patent.

Patented Apr. 2, 1912.

Serial No. 642,327.

its discharge stroke, and prevents air pressure from seating the valveswith consequent liability to breakage. The spring plate backing aids, also, in seating the valves and tends to reduce the bucklein the valve plates. The ill effects of stresses in buckled plates are minimized or overcome, largely because there is no reversal of stress in the valve plates, the outer fibers of the plate toward the seat being always in tension, and the outer fibers toward the guard being always in compression, whether the valve is open or closed, so that the ,only efi'ect of opening the valve is to increase these stresses.

In the accompanyingdrawings forming part of this specification, the invention is illustrated as applied in a valve construction of common blowing engine type, and this construction will now be described in detail, and the features forming the invention then specifically pointed out in the claims.

In the drawings, Figure 1 is a cross section through the valves, valve seats and guards. Fig. 2 is a longitudinal section on the line 2 of Fig. 1. Fig. 3 is a horizontal section on the line 3 of Fig.l.-

Referring to the drawings, A is the valve head having passages 10 and valve seats 11, the latter being divided intocomparatively narrow ports a forming a multiported seat, and B the curved guards or abutments against which the valves open, these guards being carried by supports (L The valves 1) are formed of spring plates of such length as to extend over and close the series of ports at. These are shown as formed of a single plate, but, with the usual pressures, maybe and preferably will be formed of a number of thin plates to secure the desired elasticity. The construction thus far described is of well-known type, but may be of any other suitable construction.

Referring now to the features of the present invention, the valve seat 11, instead of being flat, as usual, so that the valve 15 not under tension when closed, is curved widthwise of the valve so that the valve is bent outward or toward the guard, and under tension when closed, and the valve plates 6 are backed by spring plates under tension to press upon and close the valve, four of these plates being shown, 0', c c 0. These plates 0 c 0 c, are preferably of different widths as shown, so

that the desired elasticity of the combined valve plates and backing plates is secured, and these backing plates are preferably cut away to form a series of spring fingers acting on the valve plates. Ihe valve plates and backing plates are shown as secured together between the guards and valve supports 13 by pins passing through openings in the base of the plates, as usual with valve plates in constructions of this type, but it will be understood that they may be mounted in any other suitable manner.

It will be understood that the curved seats with plate valves under tension when closed may beused without the spring back ing plates, and such use is within the invention, but the spring backing plates secure important results in avoiding the ill.

effects of buckled valve plates, and undue wear and liability to breakage of the valves when seating, and the combination of the two features is important in enabling large valve plates to be used without the ill efiects of buckling, and in lengthening the life of such valve plates.

What I claim is:

1. In a flap valve, a valve seat slot-ted to form a plurality of ports and curved to maintain the valve under tension when closed, in combination with an elastic plate extending over the series of ports and unslotted so as to form. a continuous plate valve controlling the series of ports.

2. In a flap valve, a valve seat slotted to form. a plurality of ports and curved tomaintain the valve under tension when closed, in combination with an elastic plate extending over the sgries of ports and unslotted so as to form a continuous. plate valve controlling the series of ports, and a spring plate backing pressingthe valve toward its seat.

3. In flap valve, a valve seat slotted to form a plurality of ports and curved to maintain the .valve under tension when closed, in combination with an elasticplate extending over the series of ports and unslotted so as .to form a continuous plate valve controlling the series of ports, and a spring plate backing formed of a series of spring plates of widths decreasing from the free edge ofthe valve plate and pressing the valve toward its seat.

L'In a flap valve, a valve seat slotted 'to form a plurality of ports and curved to ward .its seat.

5. In a flap valve, the combination with a valve seat curved to maintain the valve under tension when closed, of an unslotted elastic plate valve, and a spring plate backing pressing the valve toward its seat.

6. In a flap valve, the combination with a valve seat curved to maintain the valve under tension when closed, of an unslotted elastic plate valve, and a spring plate backing pressing the valve toward its seat, and consisting of series of spring plate fingers.

7. In a flap valve, the combination with a valve seat, slotted to form a series of ports, of an elastic plate extending over the series of ports and unslotted so as to form a continuous plate valve controlling the series of ports, and a spring backing formed of a series of spring plates pressing the valve toward its seat.

8. In a flap valve, the combination with a valve seat, slotted to form a series of ports, of a valve formed of an elastic plate extending over the series of ports and unslotted so as to form a continuous plate valve controlling the series of ports, and a spring backing consisting ofaseries of spring plate fingers'pressing the valve toward'its seat,

In testimony whereof, I have hereunto set my hand, in the presence of two subscribing G. W. GRAY, Bum. E. HULL.

. witnesses. 

